ON 20040518@2:16:29 PM at page:
http://www.piclist.com/techref/microchip/math/radix/bp2b-2d8b.htm#38125.5947800926
Silvan  Minghetti[SM-bluewin-9A7] Code:

<PRE>&lt;pre&gt;
; ==========================================================
; From: Scott Dattalo
;
; This version saves one cycle.
;
        swapf   bcd, W
        andlw   0x0F            ; W=tens
        movwf   temp
        addwf   temp, W         ; W=2*tens
        addwf   temp, F         ; temp=3*tens (note carry is cleared)
        rlf     temp, W         ; W=6*tens
        subwf   bcd, W          ; W = 16*tens+ones - 6*tens


; ==========================================================
; From: Silvan Minghetti
;
; Does not require an additional temp register, but trashes
; the content of the bcd register.
;
; Expects bcd value in 'bcd', returns binary value in WREG.
; To return the binary value in 'bcd', change the last line
; to subwf bcd, F
;
        swapf   bcd, F
        rlf     bcd, W
        andlw   b'00011110'     ; WREG = tens * 2
        swapf   bcd, F

        subwf   bcd, F          ; bcd  = (tens * 16) - (tens * 2) + ones
        subwf   bcd, F          ; bcd  = (tens * 14) - (tens * 2) + ones
        subwf   bcd, W          ; WREG = (tens * 12) - (tens * 2) + ones


; ==========================================================
; From: Scott Dattalo
;
; The upper method adapted for the PIC18 Family, saves one
; more cycle.
;
        swapf   bcd, W
        andlw   0x0F            ; W= tens
        rlncf   WREG, W         ; W= 2*tens
        subwf   bcd, F          ; 16*tens + ones - 2*tens
        subwf   bcd, F          ; 14*tens + ones - 2*tens
        subwf   bcd, W          ; 12*tens + ones - 2*tens
&lt;/pre&gt;
</PRE>



ON 20040519@11:53:04 AM at page:
http://www.piclist.com/techref/microchip/math/radix/bp2b-2d8b.htm#
James Newton[JMN-EFP-786] edited the page. Difference:
http://www.piclist.com/techref/diff.asp?url=H:\techref\microchip\math\radix\bp2b-2d8b.htm&version=1